function s1_goto_dir(){
if [$# -eq 0 ];then
echo "Usage: s1_goto_dir_directory"
return 1
fi
cd "$1"
}

function s2_touch_empty_file_with_given_name(){
if [ $# -eq 0] ;then
echo "Usage: s2_touch_empty_file_with_given_name filename"
return 1
fi
touch "$1"
}

function s3_make_directions(){
mkdir -p projects/git projects/backup
cd projects
}

function s4_create_6_files(){
touch linux1_centos linux1_redhat linux1_c_programming linux2_centos linux2_redhat linux2_c-programming
}

function s5_make_directories_in_git(){
mkdir -p git/linux1 git/linux2
}

function s6_move_files_to_dir_1_or_2(){
mv linux1_* git/linux1/
mv linux2_* git/linux2/
}

function s7_create_package_and_compress(){
tar -czvf backup/git.tar.gz git
}

function s8_delete_dir_git(){
rm -rf git
}

function s9_recover_from_git_tar_gz_backup(){
tar -zxvf backup/git.tar.gz
}

function s10_create_package_and_compress(){
tar -jcvf backup/git.tar.bz2 git
}

function s11_find_and_sort_alphabetically_all_created_files_and_dirs(){
find ../projects -type f -o -type d | sort
}



function s12_get_next_15_minutes_boundary(){
current_time=$(date +%s)
next_quarter_hour=$(( (current_time + 900) / 900 * 900 ))
date -d @$next_quarter_hour + "%Y-%m-%d_%H:%M:%S"

}


